Control system and mechanism for heat processing machines



Sept. 3, 1946. V, A, FOX 2,406,822

CONTROL SYSTEM AND MEGHANISM FORHEAT PROCESSING MACHINES Original Filed Feb. 20, 1942 4 Sheets-Sheet 1 Suunto;

Gttormgs Inventor v. A.`Fox

original Filed Feb. 2o, 1942A 4 sheets-sheet 2 Sept. 3, 1946.

CONTROL SYSTEM AND MECHANISM FOR HEAT PROCESSING MACHINES Y a mww.

domegs V. A. `FOX sept. 3, 1946.

CONTROL SYSTEM AND MEGHANISM FOR HEAT PROCESSING MACHINES OriginalI Filed Feb. 20, 1942 v4 Sheets-Sheet 3 NNN.

V. A. FOX

Sept. 3, 1946.

CONTROL SYSTEM AND LMECHANISM FOR HEATPROCESSING MACHINES Original Filed Feb. 20, 1942 4 Sheets-Sheet 4 www@ Inventor 770:5

/z/dz/ nomma Patented Sept. 3, 1946 CONTROL SYSTEM AND MECHANISM FR HEAT PROCESSING MACHINESV Vernie A. Fox, Detroit, Mich.

Original application February 2), 1942, Serial No. 432,541. Divided and this application February 26, 1945, Serial No. 579,755

19 Claims.

rIhis invention relates to heat processing machines, and in particular to conveyor-type heat processing machines.

One object of this invention is to provide a heat processing machine for automatically conveying and heat-processing sheets or plates of material such as lithographed plates.

Another object is to provide a heat processing machine wherein the sheets of material to be heated are conveyed in carriers through an oven wherein they are subjected to heated air currents proceeding upwardly and downwardly in a zigzag path in the opposite direction to the direction of travel of the sheets.

Another object is to provide a heat processing machine with an endless conveyor which is normally driven from a source of power which also drives other machinery, such as coating and/or printing machinery, automatic means being provided for connecting in an auxiliary source of power when this machinery ceases operation.

Another object is to provide a heat processing machine having an oven into which articles are conveyed upwardly at the inlet and downwardly toward the outlet, thereby conserving heat by reducing the escape of the heated air normally occupying the upper portions of the oven.

Another object is to provide a heat processing machine as set forth in the previous object wherein means is provided at the outlet end of the machine for momentarily advancing the lower edge ci the sheet faster than the upper edge so that when the sheet falls as it nears the end of the conveyor it will not be damaged by slicing or buckling.

Another object is to provide a heat processing machine having a travelling conveyor with sheet carriers spaced at intervals therealong, these sheet carriers being constructed and arranged with elongated central supports to convey either large or small sheets without leaving the lower edge unsupported at its ends.

Another object is to provide a heat processing machine including an oven having an air circulating system and a heating system, automatic means being provided for delaying the starting oi the heating system a predetermined time period after the starting of the air circulating system, so that all explosive or iniiarnmable gases will be automatically cleared out of the oven before heating commences.

Another object is to provide a carrier for sheets of material consisting of a framework of rods or bars adapted to be carried by a conveyor and having provisions for leaving portions of the 2 lower edge accessible for engagement by other portions of the machine yet providing an elongated central support for several different sizes of sheets or plates.

Another object is to provide a heat processing machine as set forth in the preceding objects wherein cooling devices are provided adjacent the outlet of the machine for cooling the heated sheets or plates being processed by the machine.

In the drawings:

Figure 1 is a side elevation,'partly in section, oi the outlet end of a heat, processing machine according to a preferred embodiment of the pres ent invention;

Figure 2 is aview similar to Figure 1, but showing the inlet end and adjacent machinery;

Figure 3 is a horizontal section along the line 3--3 in Figure l, with the sheet carriers removed to disclose the construction more clearly;

Figure 4 is a 'horizontal section similar to Figure 3 but taken along the line 4 4 in Figure 2;

Figure 5 is a cross section along the line 5 5 in Figure l;

Figure 6 is a side elevation of a portion of a conveyor chain with the sheet carriers mounted thereon;

Figure 7 is a horizontal section along the line 1 1 in Figure 6;

Figure S is a vertical section along the line 3-8 in Figure 6;

Figure 9 is a detailed view of the clutch shown in the lower central portion of Figures 2 and 4;

Figure 10 is a diagrammatic side elevation of the conveyor at the outlet end of the machine, showing the means whereby the lower edge of the sheet or plate is momentarily advanced more rapidly than the upper edge so as to make it fall without injury; and

Figure 11 is a circuit diagram of the electrical, fuel and air circulation systems.

General arrangement in general, the heat processing machine of this invention includes an oven within downwardly-inclined ends for conserving heated air which is circulated through the oven by fans or blowers. An endless conveyor moves through the oven and is provided with spaced sheet carriers at intervals therealong. The sheet carriers consist of open frames (Figure 5) having gaps at the bottom thereof to permit engagement of the sheet with other conveying apparatus yet having a downwardly depending central support for the mid-portion of the lower edge of a large sheet or the end portion of a small sheet, thereby adapting the conveyor for conveying various sizes of sheets without changing the sheet carriers.

The machine conveyor is normally driven from a main motor which also drives other processing machinery, such as printing and/or coating machines. Such printing and coating machines are employed where it is desired to imprint a design or message upon the sheets, and preferably to varnish these, the oven being employed to dry the sheets after they have been thus treated. An auxiliary motor is also provided for driving the conveyor, together with automatically operative mechanism which immediately connects the auxiliary motor when the main motor is halted, thereby permitting the printing and/or coating machine to be operated intermittently while the conveyor operates continuously over a given period of time.

The spacing of the carriers along the conveyors and the mounting of the carriers at their opposite ends on a pair of parallel conveyors enables the central portions to be maintained oomparatively free from obstructions. Heaters and blowers are provided for circulating heated air upward and downward between the sheets on their carriers in a zigzag path, this heated air being finally exhausted from the oven by an exhaust fan located near the inlet of the oven, thereby causing the heated air to travel in the opposite direction to the conveyor and sheets. An electrical circuit is provided whereby the heaters are delayed from starting in operation a predetermined time after the fans are started, so that the latter may remove any inflammable gases which may have collected within the oven, thereby preventing accidental fires or explosions from such gases being ignited by the heaters. Cooling fans are provided adjacent the outlet of the machine for cooling the sheets so that they may be removed by hand if desired.

An auxiliary conveyor is provided at the outlet end of the machine for temporarily moving the lower` edges of the sheets ahead of the upper edges, so that as the carriers swing downward at the ends of the conveyor, the sheets will fall gently and without shock, thereby preventing damage to the sheets and possible injury to the machine and operators. A withdrawal conveyor is provided adjacent this auxiliary conveyor for carrying away the sheets as they are unloaded from the oven conveyor.

Machine driving mechanism Referring to the drawings in detail, Figures l to 4 inclusive show the heat processing machine of this invention as consisting of an oven generally designated I containing an endless conveyor generally designated I I having sheet carriers generally designated I 2 mounted thereon and moving in an orbital path. An auxiliary conveyor, generally designated I3 and a withdrawal conveyor generally designated I4 are provided adjacent the left-hand or outlet end of. the machine (Figures 1 and 3). Air circulation fan-s I5 are provided for circulating air heated by burners I6 through the spaces between the sheet carriers I2 and in a direction opposite the direction of travel of the conveyor II toward an exhaust fan I1 located near the inlet I8 of the oven Il! (Figure 2).

Also located adjacent the oven inlet I8 is a printing machine I8, a coating machine 2l] and a feeder 2I located therebetween. The machines I9, and 2I in themselves form no part of the present invention, except as to their main driving motor 22 which cooperates with an auxiliary driving motorI 23 to drive the machines I9, ZIJ and 2| together with the conveyor I I by the motor 22, or optionally to drive the conveyor I I alc-ne by means` of the auxiliary motor 23. The drive from the main motor shaft 24 is conveyed to the shaft 25 of the machine I9 by a belt or chain 25 interconnecting the pulleys or sprocket 21 and 2S (Figure 4).

The shaft 25 carries a pulley or sprocket 23 which drives a pulley or sprocket 30 by means of a chain or belt SI. The sprocket or pulley 38 is loosely mounted upon a shaft 32 mounted in brackets 33 and drive-s the shaft 32 through a jaw clutch 34. The shaft 32 carries a bevel gear 35 meshing with a bevel gear 36 mounted on a shaft 31. The latter is connected by means of a jaw clutch 38 to the auxiliary driving motor 23 by means of a sprocket or pulley 33 mounted loosely upon the shaft 31. The shaft 31 extends lengthwise of the machine and the pulley c1' sprocket 39 is driven by a chain or belt 13| from a pulley or sprocket 42 mounted on the shaft il of the auxiliary motor 23. The 'shaft 31 also carries a sprocket or pulley M driving a sprocket or pulley 45 by means of a chain or belt 45. The sprocket or pulley 45 is mounted upon the input shaft 41 of a reduction gear set G8, the output shaft 49 of which is mounted transversely in the machine frame members 50 and carries a pair of sprockets 5I meshing with the conveyor chains 52. The shaft 31 (Figure 1) is rotatably supported in brackets 53 mounted on the oven supports 54 and upon the outlet support 55, and at its outer end carries a sprocket or pulley 55 driving a sprocket or pulley 51 by means of a chain or belt 58. The sprocket or pulley 51 is mounted upon the input shaft 59 of a reduction gear 60, the output shaft 6I of which carries a pair of sprockets 62 driving the outlet ends of the main conveyor chains 63 of the conveyor II, the inlet ends of which are driven by the sprockets 5i upon the shaft 38. The shaft Si is likewise mounted transversely upon the outlet frame members 64. The shaft 52 also carries a pair of auxiliary conveyor sprockets driving the sprockets 68 upon the shaft El by of the belts or sprocket chains 88 of the auxiliary conveyor I3 (Figure 3). The auxiliary conveyor shaft 61 is mounted in brackets GS supported upon the outlet frame members 6G. The latter also carry brackets 18 rotatably supporting the shafts 1I carrying pulleys or sprockets 'I2 driving the belts or chains 13 of the withdrawal conveyor M. The latter is also provided with an intermediate sprocket or pulley 14 mounted upon a shaft l5 (Figure 10) supported in brackets 15 and driving an intermediate belt or chain 11.

The jaw clutches 34 and 38 are of similar construction in that they are arranged to drive their particular shaft in one direction and to slip relatively thereto in the opposite direction. Accordingly a single description suffices for each of the clutches 34 and 38 (Figure 9), the clutch 38 being selected for this purpose. The clutch 38 consists of a, driving member 18 connected to the pulley 39 and having jaw portions 19 interconnected by inclined portions 80. The pulley 18 is loosely rotatable upon the shaft 31, and seats against a collar 8| pinned as at 82 to the shaft 31. Cooperating with the clutch member 18 is a clutch member 83 having driving shoulders or jaws 84 interconnected by inclined portions 85, the clutch member 83 being keyed or splined to the shaft 31 as at 88 so as to be slidable longitudinally along i. Se

2,4ce,e22

the shaft 31 by means of a spring 81 seated against a collar 88 pinned as at 39 tothe shaft 31. In this manner each clutch 34 or 38 drives its shaft 32 or 31 in one direction but slips and clicks without driving connection when the drive is in` the opposite direction. Y

The purpose of the clutches34 and 38, as described in connection with the operation of the machine, is to permit the conveyor I I to be driven normally by the main driving motor 22 when the machines I9 and 29 are in operation, yet to permit the auxiliary driving motor 23 to drive the conveyor II when the main driving motor 22 is halted and the machines I9 and 20 are shut down. In this way the sheets or plates 90 (Figure 10) which have been printed and possibly coated are carried through the oven IU and dried even after the machines I9 and 2|) and their driving motor 22 have ceased operation.

Ouen construction The oven I9 is an elongated box-like structure with side walls 9| (Figures 3 and 5), a top 92 and a bottom 93. The oven also has inlet and outlet ends 94 and 96 respectively (Figures 1 and 2). The inlet end 94 for the purpose of conserving heat is directed downwardly toward the inlet I8. The inlet end 94 is provided with a port 9B communicating with the conduit 91 in a casing 98 containing the exhaust fan I1 for creating a suction to remove air which has traversed the oven and to discharge this air into the discharge conduit 99.

The outlet end 95 of the oven Hi (Figure 1) is Y provided with an outlet |90 communicating with a hood or vestibule IDI likewise for the purpose of conserving heat and minimizing the escape of the heated air. Baiiles |92 are distributed at intervals along the interior of the oven Il! for impeding the direct passage of the air from one end of the oven to the other so as to force it downwardly between the sheets 99 as they are carried along by the conveyor |I upon the carriers I2. One of the walls 9| of the oven is provided with doors |93 for permitting access to the burners I6 and other portions of the interior of the machine.

The burners I6 are shown as gas burners but other types may obviously be employed. The air heated by the burners is circulated by the fans or blowers I5, which are located in casings |94 having inlets |95 and outlets |06. The blowers I5 are operated by shafts |91 mounted in brackets |98 (Figure 5) secured to the walls 9 I. The shafts itl' carry pulleys |99 driven by belts ||0 from pulleys ||I upon the shafts II2 of motors ||3. The latter are mounted upon brackets ||4 beneath the longitudinal frame members I |5 interconnecting the oven supports 54. The brackets H4 are also matched by corresponding brackets H9 on the opposite side of the machine (Figure 5) and these together support the angle guide rails I I 1 upon which the conveyor chain 63 travels on its return path.

rl'he interior of the oven is likewise provided with angle guide rails I I8 which support the conveyor 53 in its travel through the oven, and these guide rails I I3 are inclined downwardly at the opposite ends of the oven. Cooling fan motors I |9 provided with fans |25) in casings |2| are located near the outlet end 95 of the oven so as to cool the sheets or plates 90 as they emerge from the vestibule or hood IDI.

Near the oven outlet |00 the guide rails I i8 are supported by a cross member 122 and elsewhere within the oven by cross members |23 (Figure 5).

The latter are connected to longitudina1 angle members |24 and also carry spaced longitudinal members |25 between which the air may circulate freely.

Conveyor and carrier construction y The conveyor II and carriers I2 include the conveyor chains E3 mounted upon the guide rails IIS and ||1 as previously described. The conveyor chains 63 consist of links |26 and |21 pivotally connected to pivot pins |28 carrying rollers |29 which roll along the top edges of the guide rails H1 and ||8. The pivot pins |28 are provided on one side with heads |29 and on the other side are held in place by cotter pins |30. Mounted adjacent the links |21 are angle members |3| which extend out over the links |21 and provide rests for the lower edges of the sheets or plates 99 which form the work pieces handled by the machine. Adjacent the opposite links |26 are mounted channel members |32 having aligned apertures |33 and |34 (Figure 8) through which pass the side portions I35of the carriers I2. These side portions |35 are bifurcated as at |35 and spread apart after their insertion so as to prevent their accidental withdrawal.

The side portions |35 are bent inwardly to form top portions |33` and |31. The top portion |31 is bent downwardly in a diagonal portion |38 (Figure 5) to the portion |35 in any suitable way, as by spot welding. The top portion |36 is bent diagonally downwardly in a portion |49 which is secured at the top portion |4| to the diagonal portion |38. A diagonal portion |42, also secured at the top portion |43 to the diagonal portion |39, continues downwardly to a junction at the top portion |44 with the other side member |35. Secured at its opposite ends |45 to the diagonal members |38 and |42 is a U-shaped downwardlyextending frame |46 having side portions |41 and a cross portion |48 at the bottom thereof. Secured to the bottom portion |48 at the corners of the frame |46 are sheet supports |49. The sheet supports are inclined upwardly as at |49a (Figure 6) and serve to support the lower edges of the sheets 99.

The carriers I2 are thus spaced at intervals along the chain 63 and are inclinedupwardly so that the sheets or plates 98 rest in inclined positions as they travel through the oven (Figure 6). The downwardly extending frame |45 with its supports |49 enables sheets smaller than the maximum size sheets to be conveyed, hence there is no necessity for changing the carriers I2 for different sizes of sheets. Moreover, the open spaces between the side members |35 and |46 permit the lower edges of the plates to be engaged by the auxiliary conveyor 53 (Figure 10) which passes thro-ugh these spaces and serves to advance the lower edges of the sheets 9|] ahead of their upper edges as previously described above.

Heating, driving, and air circulating systems an electrical safety circuit controlled by thermostatic switches so that the gas burner valves remain open only while the temperature is high and close when the temperature drops. A timedelay relay inserted in the circuit of the master magnetic valve delays the opening of this valve until the blower motors H3 have been in operation a predetermined length of time so as to clear the oven of inflammable or explosive gases before the burners can be ignited.

In particular, the electrical system consists of power current supply lines |50 to |52 having a single throw switch |53. This controls the energization of the blower Amotor energization lines |54, |55 and |56 leading to the blower motors ||3 and H9 and also to the exhaust ian motor |1. Consequently when the switch |53 is closed, the blower motors I1, ||3 and H9 start in operation, permitting the blowers to clear the interior of the oven of all explosive gases. Leading from the power lines |54, |55 and |56 are auxiliary power'lines |51, |58 and |59 for energizing the air compressor motor |60 which operates the air compressor |5|. The latter has an intake |62 and a discharge conduit |63 leading by branch lines |64 to electrically controlled proportional mixers |65 from the gas supply line |61 by way of the magnetically operated valve |68, the gas supply line |69, the branch lines |16, the manual gas valves |1| and the magnetically operated gas valves |12. From the proportional mixers |65 the conduits |13 lead to the burners i6. Associated with each burner I6 is a thermocouple |14 which generates current when it is heated bythe burner |6. This current is conveyed through the lines and |18 to the operating coil of the normally closed gas valve |12 to maintain it open while the burners I5 are alight but to permit the gas valves |12 to close when the burners are not lighted. The normally closed magnetic valves |12 are provided with manually operated valve members |11 by which the valves |12 may be manually opened when the burners |6 are ignited.

The proportional mixers |65 are under the control oi thermostatic bulbs |18 connected by the lines |19 to the temperature control instruments |80 which in turn are connected by the lines |8|,

|82 and |68 to the proportional mixers |65. The f latter are likewise under the control of the switches |84 connecting the lines |85 and |86 to the lines |51 and |88. The lines |81 and |88 are energized from the current supply lines |89 and |90 under the control of the single throw switch |9|.

The electrical circuit (Figure 11) includes the contactor switches |92, |93 and |94 having operating coils |95, |96 and |91 respectively connected either to the power lines |54 and |56 or to the power lines |51 and |56. The contactor switches |92, |93 and |94 are normally open, and are closed by the energization of their operating coils |95, |96 and |91 in response to the closing of the switch |53. The latter, when closed, energizes the blower motors ||3 and causes the blowers to operate.

Running from the current line |88 is a line |98 which continues in the line |99 beyond the contactor switch |92. The line |99 is provided with a series of normally open air-responsive switches 200 which are closed automatically when the blower motors ||3 are operating, thereby permitting current to be transmitted to the contactor |93, thence through the line 20| through the contactor |94 to the line 202 leading to the timedelay relay 203, from the opposite pole of which a line 204 leads to the current supply line, |81. Thus, when the blower motors ||3 are operated, the contactor switches |92, |93 and |94 close and 8 the switches 200 likewise close to permit current to energize the time-delay relay 203. After the latter has run through its cycle, it energizes the operating coil of the gas supply valve |68 through the lines 205 and 206 opening this normally closed valve. Thus, gas is not admitted to the gas line |66 until the blower motors |3 have been operating a predetermined time.

Operation In the operation of the machine of this invention, the main and auxiliary driving motors 22 and 23 are energized to cause the conveyor to pursue its orbital path through the oven I0 and also to drive the printing press I9 and coating machine 20. The switches |53 are then closed, energizing the blower motors l1, ||3 and ||9 and causing air to flow through the oven in a circuitous path opposite the direction travel of the conveyor The bailles |02 cause the air to move up and down between the carriers I2, so that the air follows a zigzag path as indicated by the arrows in Figures 1 and 2.

The operator now closes the switches ISI and |84 to energize the control circuit. The air 0perated valves 280 then close under the iniluence of the blast of air from the blowers, thereby closing the circuit to the time-delay relay 203 through the contactor switches |92, |93 and |94, which have been closed since the blower motors ||3 were energized by the closing of the switch |53. After a predetermined time, the gas valve |68 opens after being energized by the time-delay relay at the end of its cycle and fuel gas passes from the conduit |61 into the conduits |69 and |18. Meanwhile, air has been supplied by the compressor |5| to the conduits |63 and |64 leading to the proportional mixers |65. It is, of course, assumed that the manual valves |65` and |1| have been opened.

The operator now opens the normally closed gas valves |12 by pressing upward on the valve members |11, permitting gas to flow from the conduits |10 into the proportional mixer |65. 'I'he motors of the latter have been energized through the lines |85 and |86 by the closing of the switches |84, and consequently mixed gas is supplied to the burners |6 through the conduits |13, The operator lights the burners I6, holding up the valve members |11 manually until the heating of the thermocouples |14 generates enough current to energize the operating coils of the magnetic gas valves |12, a suicient amount to hold them open. If the temperature rises and falls in the oven, the thermostatic bulbs |18 and the temperature control instruments |80 so regulate the proportional mixers |65 that the ratio of air to gas remains the same while the volume is varied in order to maintain a substantially constant temperature within the oven I0.

In the meantime, the printing machine I9 and coating machine 20 have been imprinting designs on the sheets of the tin or other material, and these have been deposited upon the carriers |2 as the conveyor moves them through the oven. The heated air circulates in a zigzag path through the spaces between the carriers and the sheets, and follows a general direction opposite to the direction of travel of the conveyor due to the operation of the exhaust fan 98. As the sheets or plates 90 emerge from the vestibule |0|, they are cooled by the drafts of cool air coming from the cooling fans |20 operated by the motors H9.

It is to be noted that the fan |20 and blower |5 adjacent the outlet of the oven are arranged so that cool air will b e directed upwardly through and between the plates I2 and will be further directed into the oven by reason of the hood I!!! so as to be forced or drawn downwardly through the sheets l2 tothe intake of said blower I5. In this manner, the heat from the oven may be prevented from escaping to the surrounding atmosphere so that operation of the oven may be carried out during summer months without unduly heating the atmosphere in the building in 4which the oven is installed.

While the carriers I2 move over the auxiliary conveyors t8, the latter extend into the spaces in the bottom edges of the carriers I2, engaging the bottom edges of the sheets 98. Since the auxiliary conveyors 68 are moving Vmore rapidly than the main conveyor chains 63, the bottom edges on'f the sheets or plates @il are moved ahead of their top edges (Figure so that as the carriers I2 swing downwardly around the shaft 62 as 'anv axis, the sheets .'35 lie'iiat against the back of each carrier, until they arrive at the withdrawal'conveyors 'l2 and "il, The latter` conveyors then cnvey the sheets to the next stage of operations such as the forming of cans from the sheets.

If at any time the gas supply is accidentally interrupted, the therinocouples |14 immediately cease to generate current and the magnetic valves Vig automatically close. This .cuts off the supply of gas to the burners i6 which .cannotthereafter be lighted until the switches I'l2 are `manually opened as previously described, Meanwhile, the auxiliary driving motor 23 has also been .operating butit has failed thus far to drive the shaft 3l since the automatic body clutch ,38 prevents this by the slippage of the clutch members 'I8 and 83 relative to each other (Figure 9).

If now the desired quantity of sheets or plates have been printed and coated and the main driving motor 22 is shut down to halt the machines I9 and 20, the shaft 2,5 andthe pulley or sprocket Bil immediately come to rest. Due to the provision of the automatic jaw clutches .34 `and 38, ,however, the auxiliary ydriving motorv 2.3 now .drives the "shaft 3l through the 4jaw clutch 38 while the clutch members of the jaw ,clutch 3,4 slip `relatively to each other.

This `is a division of my application filed February 20, 1942, for Heat processing machine, Serial No. 432,541.

While a specific embodiment of the invention has been described and illustrated, it will be understood that various modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

1. In a heat processing machine, an oven, a burner in said oven, means for supplying fuel to said burner, normally closed means for controlling the flowrof fuel through said fuel supplying means, an air circulatcr positioned to move heated rair from said burner through said oven,

:means for driving said air circulatcr, time delay means responsive to the lapse of a predetermined time period following the starting of said air circulator driving means for opening said fuel flow controllin-g means, and means for additionally `delaying the opening of said fuel flow control means whereby to remove iniiammablegases from said oven before permitting igniting of Vsaid burner;

2. In Va. heat processing machine, an oven, a

Aburnerin said oven,rmeans forsupplyng fuelto .said burner. normally .closed means for @11u91- lins the -iiow of Vfuel through Said ,fuel supplying means, air circulator positioned to move heated air `from Said burner thrwsh said Oven. means for driving said air circulaton means for controlling the normally closed fuel flow control means mounted `adjacent saidair circulator responsive to the flow of air` at said circulator for opening said fuel ilow controlling means a predetermined time period after said air circulators have been set in operation, and temperature responsive means Vfor controlling said fuel iiow means subsequent to the ignition of said fluid flowing through said burner. y

3. In a heat processing machine, an oven, a burner in said oven, means for supplying fuel to said burner, normally closed means for controlling `the flow of fuel through said fuel supplying means, an air circulator positioned to move heated air from said burner through said oven, means for driving said air circulator, time delay means responsive to the lapse .of a predetermined time period following the starting of said air circulator driving means for opening said fuel flow controlling means whereby to remove inflammable gases from said oven before permitting igniting of `said burner, and means responsive to the flow of air at said circulator for rendering said time delay Ymeans operative.

ln a heat processing machine, an oven, a burner in said oven, electro-magnetically controlled means for controlling the flow of 4fuel to said burner, normally closed manually controlled valve means interposed between said burner and electro-magnetically controlled means, means ad jacent the burner "responsive to ignition of said burner for maintaining said valve means open, blower means for supplying air to said burner and creating a `forced draft in said oven, electric .power mean-s for driving said blower means, an electric .ciruitconnected with a source of electrical energy ;for said electric power means, and means in said electric circuit for permitting operation of said Ablowermeans prior to the energiza- -tion of said `electro-magnetically controlled fuel r supply,means and the flow of vfuel to said burner.

`5. In a heat .processing machine, Aan oven, a series, of Vfan blowers insaid oven for directing air therethrough, aburner located in said oven, electromagnetically ,controlled valve means for controlling the ilowof fuel to said burner, a manually controllednormally Yclosed valve interposed ben tWeensa-id burner and eleciromagnetically controlled valve means, an electric circuit connecting said blowers `and electromagnetic valve means, a source of `electric energy for operating said blowers, time .delay switch means in .said circuit to permit energization of said,electromagnetically ,controlledfvalve means after the blower means has been in operation 4for a predetermined time period, ,switch means in said circuit controlled by .the operation of said blowers for interrupting said circuit when ,the blowers ,are in operation, and electrical f meanfs mounted adjacent the` burner for `maintaining" .said manually `controlled normally closed valve .means open when said burner is ignited. Y

6. aheat processing machine, 4an oven, a sen ries of fan blowers Vin saidoven for directing air therethrough, ,a burner located .in said ovene1ecvtromagnetfically .controlled-valve means for controlling the flow of fuel tosaid burner, a manually controlled normally closed-yalve interposed between salti` burner and eleetromaenetially c011- rtm1-led Nellie :means lan slegtricircuit connecting said blowers and electromagnetic valve means, a source of electric energy for operating said blowers, time delay switch means in said circuit to permit energization of said electromagnetically controlled valve means after the blower means has been in operation for a predetermined time period, switch means in said circuit controlled by the operation of said blowers for interrupting said circuit when the blowers are in operation, electrical means mounted adjacent the burner for maintaining said manually controlled normally closed valve means open when said burner is ignited, and means in said oven responsive to the ternperature of the heated air to regulate the fuel and air supply to said burner.

7. In a heat processing machine, an oven, a series of blowers arranged in said oven for directing air therethrough in a zigzag path, a series of burners mounted in said oven arranged adjacent each blower, an electric circuit, motor means connected in said circuit for driving said blowers, a fuel flow path for supplying said burners with fuel, electromagnetic Valve means in said fuel flow path, time delay means in said circuit adapted to be energized upon energization of said blower, motor means for operating said electromagnetic valve means and controlling fuel now along said fuel flow path, a manually controlled normally closed valve means between the fuel iiow path and each burner, and means adjacent each burner responsive to the temperature therein for maintaining said manually controlled valve means in an open position.

8. In a heat processing machine, an Oven, a series of blowers arranged in said oven for directing air therethrough in a zigzag path, a series of burners mounted in said oven arranged adjacent each blower, an electric circuit, motor means connected in said circuit for driving said blowers, a fuel flow path for supplying said burners with fuel, electromagnetic valve means in said fuel flow path, time delay means in said circuit adapted to be energized upon energization of said blower, motor means for operating said electromagnetic valve means and controlling fuel flow along said fuel flow path, a normally closed manually operable valve means interposed between the fuel flow path and each burner, means adjacent each burner responsive to the temperature thereof for maintaining said valve means open, air mixing means associated with each burner, andtemperature responsive means in said oven for regulating the proportion of air and gas directed to each burner.

9. In a heat processing machine, an oven, a series of blowers arranged in said oven for directing air therethrough in a zigzag path, a series of burners mounted in said oven varranged adjacent each blower, an electric circuit, motor means connected in said circuit for driving said blowers, a fuel ow path for supplying said burners with fuel, electromagnetic valve means in said fuel flow path, time delay means in said circuit adapted to be energized upon energization of said blower, motor means for operating said electromagnetic valve means and controlling fuel flow along said fuel flow path, a normally closed manually operable valve means in said fuel ow path between the electromagnetic Valve means and each burner, and temperature responsive means adjacent each burner adapted to maintain said last-named valve means in an open position.

10. In a heat processing machine, an oven, a series of blowers arranged in said oven for directing air therethrough in a zigzag path, a series of burners mounted in said oven arranged adjacent each blower, an electric circuit, motor means connected in said circuit for driving said blowers, a fuel iiow path for` supplying said burners with fuel, electromagnetic Valve means in said fuel flow path, time delay means in said circuit adapted to be energized upon energization of said blower, motor means for operating said electromagnetic valve means and controlling fuel fiow along said fuel flow path, a manually controlled normally closed valve means between the fuel flow path and each burner, means adjacent each burner responsive to the temperature therein for maintaining said manually controlled Valve means in an open position, a control circuit for said electric circuit, and normally open switch means in said circuit adapted to be closed by the increased air pressure from said blowers for maintaining said electric circuit closed.

11. In a heat processing machine, an oven, a series of blowers mounted in said oven for directing heated air through said oven, a series of burners mounted in said oven adjacent said blowers, a series of air and gas mixers, blower means for supplying said mixers with air, a source of fuel connected with each of said mixers, an electromagnetically controlled valve interposed in the iiow path between the source of fuel and said air and gas mixers, normally closed valve means adapted to be manually opened interposed in the fuel flow path between the electromagnetically controlled Valve and each air and gas mixer, an electric circuit for supplying current for operation of said blowers and blower means, a control circuit for said electric circuit, relay switch means in said electric circuit for energizing said control circuit, time delay means in said control circuit for energizing said electromagnetically controlled valve after said electriccircuit has been closed a predetermined timel period, pressure responsive switch means in said control circuit located adjacent each of said blowers for maintaining said electromagnetically controlled valve energized, and means adjacent each burner for maintaining said normally closed Valve means open when the temperature adjacent each burner has reached a predetermined temperature degree.

l2. In a heat processing machine, an oven, a series of blowers mounted in said oven for directing heated air through said oven, a series of burners mounted in said oven adjacent said blowers, a series of air and gas mixers, blower means for supplying said mixers with air, a source of fuel connected with each of said mixers, an electromagnetically controlled Valve interposed in the iiow path between the source of fuel and said air and gas mixers, normally closed valve means adapted to be manually opened interposed in the fuel fiow path between the electromagnetically controlled Valve and each air and gas mixer, an electric circuit for supplying current for operation of said blowers and blower means, a control circuit for said electric circuit, relay switch means in said electricV circuit for energizing said control circuit, time delay means in said control circuit for energizing said electromagnetically controlled Valve after said electric circuit has been closed a predetermined time period, pressure responsive switch means in said control circuit located adjacent each of said blowers for maintaining said electromagnetically controlled valve energized, means adjacent each burner for maintaining said normally closed valve means open when the temperature adjacent each burner has reached a predetermined temperature degree, and temperature 13 responsive means in said oven for regulating said air and gas mixers.

13. In a heat processing machine, an oven ,a series of blowers mounted in said oven for directmg heated air through said oven, a series. of burners mounted in said oven adjacent said blowers, a series of air and gas mixers, blower means for supplying said mixers with air, a source of fuel connected with each of said-mixers, an electrcmagnetically controlled valve interposed in the flow path between the sourceof fuel andsaid air and gas mixers, normally closed valvemeans adapted to be manually opened interposed in the fuel flowl path between the electromagnetically controlled `Valve and each air and gas mixer, an electric circuit for supplying current for operation of said blowers and blower means, a control circuit for said electric circuit, relay switch means in said electric circuit for energizing said control circuit, time delay means in said control circuit for energizing said electromagnetically controlled valve after said electric circuit has been closed a predetermined time period, pressure responsive switch means in said control circuit located adjacent each oi. said blowers for maintaining said electromagnetically controlled valve energized, and means adjacent each burner for maintaining said normally closed Valve means open when the temperature adjacent each burner has reached va predetermined temperature degree, said lastnamed means comprising a thermocouple disposed adjacent each burner for generating electric energy to maintain said normally closed valve means open.

lll. In a heat processing machine, an oven, a series of blowers mounted in said oven in spaced apart relation along said oven for directing air therethrough, an exhaust blower mounted adjacent the entrance of said oven, a series of fuel burners mounted in said oven adjacent said firstmenticned blowers, a fue] supply manifold having one end connected to a source of fuel and the branch pipe thereof connected to said burners, an electromagnetically controlled valve interposed between said source of fuel and said manifold, a series of gas and air mixers interposed in the branch pipes of said fuel supply manifold, a second manifold for supplying air to said burners having the branch pipes thereof connected to said air and gas mixers, blower means associated with said last-named manifold, a normally closed manually operable valve interposed in each of the branch pipes of the fuel supply manifold between the electromagnetically controlled valve and said air and gas mixers, electric motors for each of said blowers and blower means, an electric circuit for supplying electric energy to said electric motors whereby air will be admitted to said mixers and oven simultaneously, electromagnetic relay switch means in said circuit, a control circuit adapted to be closed upon energization of said electric circuit and said electromagnetic switch means, time delay switch means in said control circuit for controlling the energization.A of said electromagnetically controlled valve means, and air pressure operated switch means in said control circuit mounted adjacent said first-named blowers for interrupting said control circuit in the event of failure of said series of blowers.

l5. In a heat processing machine, an oven, a series of blowers mounted in said oven in spaced apart relation along said oven for directing air therethrough, an exhaust blower mounted adjacent the entrance of said oven, a series of fuel burners mounted in said ovenadjacent said firstmentioned blowers, a fuel supply manifold having one end connected to a source of fuel and the branch pipe thereof connected to said burners, an electromagnetically controlled valve interposed between said source of fuel and said manifold, a series of gas and air mixers interposed in the branch pipes Aof said fuel supply manifold, asecond manifold for supplying air to said burners having Ythe branch pipes thereof connected to said air and gas mixers, blower means associated with said last-named manifold, a normally closed manually operable Valve interposed in each of the branch pipes of the fuel supply manifold between the electr-omagnetically controlled valve and said air and gas mixers, electric motors for each of said blowers and blower means, an electric circuit for supplying electric energy to said electric motors whereby air will be admitted to said mixers and oven simultaneously, electromagnetic relay switch means in said circuit, a control circuit adapted to be closed upon energization of said electric circuit and said electromagnetic switch means, time delay switch means in said control circuit for controlling the energization of said electromagnetically controlled valve means, air pressure operated switch means in said control circuit mounted adjacent said first-named blowers for interrupting said control circuit in the event of failure of said series of blowers, and thermoelectric means mounted adjacent each burner for maintaining said normally closed oven in an open position after the burners have been ignited.

16. In a heat processing machine, an oven, a series of blowers mounted in said oven in spaced apart relation along said oven for directing air therethrough, an exhaust blower mounted adjacent the entrance of said oven, a series of fuel burners mounted in said oven adjacent said firstmentioned blowers, a fuel supply manifold having one end connected to a source of fuel and the branch pipe thereof connected to said burners, an electromagnetically controlled Valve interposed between said source of fuel and said manifold, a series of gas and air mixers interposed in the branch pipes of said fuel supply manifold, a second manifold for supplying air to said burners having the branch pipes thereof connected to said air and gas mixers, blower means associated with said last-named manifold, a normally closed manually operable valve interposed in each of the branch pipes of the fuel supply manifold between the electromagnetically controlled Valve and said air and gas mixers, electric motors for each of said blowers and blower means, an electric circuit for supplying electric energy to said electric motors whereby air will be admitted to said mixers and oven simultaneously, electromagnetic relay switch meansin said circuit, a control circuit adapted to. be closed upon energization of said electric circuit and said electromagnetic switch means, time delay switch means in said control circuit for controlling the energization of said electromagnetically controlled valve means, air pressure operated switch means in said control circuit mounted adjacent said rst-named blowers for interrupting said control circuit in the event of failure of said series of blowers, and thermostatic means mounted in said oven for controlling the air and gas mixers to thereby maintain the proportion of gas and air admitted to said burners equalized.

17. In a heat processing machine, an oven, a, series of blowers mounted in said oven in spaced apart relation along said oven for directing air therethrough, an exhaust blower mounted adl5 jacent the entrance of said oven, a series of fuel burners mounted in said oven adjacent said firstmentioned blowers, a fuel supply manifold having one end connected to a source of fuel and the branch pipe thereof connected to said burners, an electromagnetically controlled valve interposed between said source of fuel and said manifold, a series of gas and air mixers interposed in the branch pipes of said fuel supply manifold, a second manifold for supplying air to said burners having the branch pipes thereof connected to said air and gas mixers, blower means associated with said last-named manifold, a normally closed manually operable valve interposed in each of the branch pipes of the fuel supply manifold between the electromagnetically controlled valve and said air and gas mixers, electric motors for each of said blowers and blower means, an electric circuit for supplying electric energy to said electric motors whereby air will be admitted to said mixers and oven simultaneously, electromagnetic relay switch means in said circuit, a contro1 circuit adapted to be closed upon energization of said electric circuit and said electromagnetic switch means, time delay switch means in said control circuit for controlling the energization of said electromagnetically controlled valve means, air pressure operated switch means in said control circuit mounted adjacent said first-named blowers for interrupting said control circuit in the event of failure of said series of blowers, thermoelectric means mounted adjacent each burner for maintaining said normally closed valve in an open 16 position after the burners have been ignited, and thermostatic means mounted in said oven for controlling the air and gas mixers to thereby maintain the proportion of gas and air admitted to said burners equalized.

V18. In a heat processing machine, an oven, means for heating said oven, a conveyor movable through said oven, main driving means including a drive shaft, motor and reduction gearing, means connecting said drive shaft and gear reduction, electric means connecting said motor and shaft to drive said conveyor, auxiliary driving means drivingly engaging said shaft operable to drive said conveyor, and a clutch connecting said shaft and auxiliary driving means responsive to the cessation of operation of said main driving means for rendering said auxiliary driving means 0perative to drive said conveyor.

19. In a heat processing machine, an oven. means for heatingk said oven, a conveyor movable through said oven, main driving means including a drive shaft, motor and reduction gearing unit, means connecting said drive shaft and gear reduction unit, clutch means connecting said motor and shaft, said driving means being operable to drive said conveyor, auxiliary driving means operable to drive said conveyor, and automatic operable clutch mechanism connecting said shaft and auxiliary driving means responsive to the cessation of operation of said main driving means for rendering said auxiliary driving means operative to drive said conveyor.

VERNIE A. FOX. 

